Altair Hypercam 533C

Discussion of features and issues relating to Altair Astro Cameras
Rick_A
Posts: 4
Joined: Fri Jun 10, 2022 7:45 am

Altair Hypercam 533C

#1

Post by Rick_A »

Hi
This is my first dedicated astro camera so please excuse a fair amount of ignorance. I did a Sharpcap sensor analysis and according to the results the unity gain should be around 200 but everyone talks about setting gain at 100 as if that's unity gain. Can somebody explain why the discrepancy?
Many thanks.
User avatar
admin
Site Admin
Posts: 13177
Joined: Sat Feb 11, 2017 3:52 pm
Location: Vale of the White Horse, UK
Contact:

Re: Altair Hypercam 533C

#2

Post by admin »

Hi,

I think you are getting the 100 gain number from the equivalent ZWO camera - in that camera when you get to gain=100, the camera switches to HCG (lower noise) mode and gives approximately unity gain. In ZWO cameras 100 gain means brightening the image by a factor of just over 3, with zero being the minimum gain.

Altair cameras work differently - 100 is the minimum gain, 200 is twice as bright as 100, 300 is three times as bright as 100, etc.

Now, digging into this made me find a bug in the current SharpCap that will switch on HCG for the Altair533 from gain=200 (should be gain=300). I'm going to fix that bug, since it means that with the current versions gains of between 2x and 3x brightness are not available at all in SharpCap.

Anyway, if you are using a version of SharpCap you have installed today, use 200 gain to get HCG and unity gain. From next week's version, use gain=300

cheers,

Robin
Rick_A
Posts: 4
Joined: Fri Jun 10, 2022 7:45 am

Re: Altair Hypercam 533C

#3

Post by Rick_A »

Many thanks Robin and will do as you suggest with Sharpcap. If I use other capture software for DSO's such as APT am I right to use Gain of 200?
All the best Richard
Rick_A
Posts: 4
Joined: Fri Jun 10, 2022 7:45 am

Re: Altair Hypercam 533C

#4

Post by Rick_A »

Sorry, I should have added "with HGC enabled".
User avatar
admin
Site Admin
Posts: 13177
Joined: Sat Feb 11, 2017 3:52 pm
Location: Vale of the White Horse, UK
Contact:

Re: Altair Hypercam 533C

#5

Post by admin »

Hi Rick,

I'd go with 300 for APT etc, on the grounds that they probably do *not* have the same bug as SharpCap to do with the switchover being at the wrong place. You want to make sure you are in HCG mode, so better to be 300 and sure of that than 200 and perhaps not.

cheers,

Robin
Rick_A
Posts: 4
Joined: Fri Jun 10, 2022 7:45 am

Re: Altair Hypercam 533C

#6

Post by Rick_A »

Thanks a lot Robin for yr patience.Rick
savcom
Posts: 4
Joined: Thu Jun 23, 2022 6:37 pm
Location: Wiltshire, UK

Re: Altair Hypercam 533C

#7

Post by savcom »

admin wrote: Fri Jun 10, 2022 12:52 pm Hi,

I think you are getting the 100 gain number from the equivalent ZWO camera - in that camera when you get to gain=100, the camera switches to HCG (lower noise) mode and gives approximately unity gain. In ZWO cameras 100 gain means brightening the image by a factor of just over 3, with zero being the minimum gain.

Altair cameras work differently - 100 is the minimum gain, 200 is twice as bright as 100, 300 is three times as bright as 100, etc.

Now, digging into this made me find a bug in the current SharpCap that will switch on HCG for the Altair533 from gain=200 (should be gain=300). I'm going to fix that bug, since it means that with the current versions gains of between 2x and 3x brightness are not available at all in SharpCap.

Anyway, if you are using a version of SharpCap you have installed today, use 200 gain to get HCG and unity gain. From next week's version, use gain=300

cheers,

Robin
Hi Robin - I've been trying to make the most of my Altair Hypercam 533C and I think this information may help me with my issues.

Once we get the updated SharpCap I assume we'll need to rebuild (or expand) our Dark libraries to cope with the gain settings - but should we also re-run the sensor analyses for our Altair cameras? (I have the 533 and a GPCAM3 290C)

Thanks
User avatar
admin
Site Admin
Posts: 13177
Joined: Sat Feb 11, 2017 3:52 pm
Location: Vale of the White Horse, UK
Contact:

Re: Altair Hypercam 533C

#8

Post by admin »

Hi,

yes, you should re-run the analysis and re-create the dark library for any darks with gains between 200 and 300 (inclusive).

cheers,

Robin
rockinrome
Posts: 2
Joined: Wed Jan 04, 2023 9:22 am

Re: Altair Hypercam 533C

#9

Post by rockinrome »

This is great information here, thanks.
Sorry to resurrect this post but I wish to clarify a point regarding the HCG setting.

With the Altair 533C do I need to specifically select the HCG setting in (say) NINA / APT to get HCG to work, or do I simply set Gain to 301 (without HCG selected) to force it into this mode.

NOTE - I've read that NINA needs you to set the gain properly if switching on HCG as it uses the camera multiplier (3.05x in this case), so if GAIN at 101 and HCG set - this is actually Gain 303 and therefore enables HCG in the camera. If you have set 301 Gain already then this pushes up to 903 Gain and is way too much.

Thanks in advance for any help that can be given.

Kind regards
Matthew
"They mostly come out at night. Mostly."
User avatar
admin
Site Admin
Posts: 13177
Joined: Sat Feb 11, 2017 3:52 pm
Location: Vale of the White Horse, UK
Contact:

Re: Altair Hypercam 533C

#10

Post by admin »

Hi Matthew,

I can speak for SharpCap and the Altair ASCOM driver from direct knowledge:

* SharpCap - LCG/HCG switch is automatic as described above
* Altair ASCOM driver - there is a choice in the settings for the ASCOM driver - auto (like SharpCap), LCG or HCG

I suspect a lot of other software will display them as separate controls, in which case you need to (as you say) take care when setting the gain as HCG + 300 gain is really ~900 gain. A quick test image taken of the same daytime target in each piece of software will help reveal how much gain you are getting if you are unsure.

cheers,

Robin
Post Reply